Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L21/00—Compositions of unspecified rubbers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S525/00—Synthetic resins or natural rubbers -- part of the class 520 series
  • Y10S525/938—Polymer degradation

Definitions

• thermoplastic polymer compositions characterized by high melt flow which are pelletizable and can be conveniently converted into fabric and film that is drapable.
• fabric can be produced by knitting, tufting, wool felting, weaving, or by non-woven means.
• a non-woven fabric can be produced by bonding and/or interlocking fabric materials by mechanical, chemical, thermal or solvent means, or through a combination of these means in accordance with ASTM D-1117-63, Part 24, Page 315 (1965).
• non-woven denotes a web or mat of fibers held together with bonding materials.
• Non-woven fabrics were originally developed as inexpensive substitutes for woven fabrics, and have gradually entered markets for which they are uniquely suitable, such as facings or top sheets in diapers, incontinent pads, bed pads, sanitary napkins, hospital gowns, and the like.
• Sources of useable fibers include cellulosics, nylon, polyesters, polyolefins, fluorocarbons, and inorganic fibers.
• Other polymers include polyvinyl alcohol, polyvinyl acetate, vinyl chloride polymers, styrenebutadiene copolymers, acrylic resins, polyurethanes and the like.
• Film materials can be prepared by cast or blown extrusion, compression molding, or other methods known to those skilled in the art.
• U.S. Pat. No. 4,368,233 to Barkis et al discloses extrusion coating compositions for woven and non-woven polyolefin substrates which employ mixtures of high density polyethylene with other polyolefins.
• U.S. Patent No. 4,426,417 to Meitner et al discloses a wiper comprised of a matrix of non-woven fibers incorporating a staple fiber mixture containing synthetic and cotton fibers.
• U.S. Pat. No. 4,380,570 to Schwarz discloses an apparatus and process for forming fine fibers from molten thermoplastic polymers by extruding the molten polymer through orifices in nozzles at low melt viscosity and high temperatures.
• the molten fibers are accelerated to near sonic velocity by gas blown in parallel flow through small orifices surrounding each nozzle.
• U.S. Pat. No. 4,568,596 to Johnson discloses a non-woven, texturized fabric produced by embossing a molten film of a polymer blend of high density polyethylene and polystyrene.
• U.S. Pat. No. 2,631,954 to Bright discloses a film composition formed from ethenoid polymers with an average molecular weight greater than 2500, obtained by heating ethylene in the presence of one or more organic compounds containing one or more double bonds and capable of forming dimers or high polymers.
• U.S. Pat. No. 2,726,230 to Carlson discloses plastic acrylic interpolymers formed by polymerizing a monomeric mixture containing an acrylic ester and an olefinically unsaturated carboxylic acid.
• U.S. Pat. No. 4,500,681 to Shulman relates to a thermoplastic elastomeric blend of a polyolefin, an isobutylene-backbone elsstomer, and a copolymer of ethylene with an unsaturated ester of a lower carboxylic acid.
• U.S. Pat. No. 4,100,240 to Bassani discloses a process for extruding a low viscosity fiber containing a polysiloxane liquid polymer precursor which reacts when heated to form a cross-linked fiber reinforced polysiloxane elastomer.
• U.S. Pat. No. 4,399,249 to Stammusas discloses a block copolymer blend containing at least two end thermoplastic polymer blocks and one mid-polymer block, wherein the end block is a non-elastomeric polymer block, and the mid-block is an elastomeric polymer block.
• Drapability is especially important as a comfort property in situations where the film or fabric comes into contact with human skin for extended periods of time, on the order of several hours.
• Pelletizability is an important characteristic because pellets can be extruded like a thermoplastic and converted to film or fabric at high production rates in an extruder adapted with the necessary equipment for final conversion to the desired shape and form.
• the present invention relates to a thermoplastic pelletizable polymer composition
• a thermoplastic pelletizable polymer composition comprising an oligomer or degraded polyolefin and an olefinic elastomer.
• the composition can also include a polyolefin thermoplastic polymer with or without a functional group.
• the composition when converted to a film or fabric meets the criteria of drapability, low hardness on the Shore A scale, high melt flow and reprocessability.
• thermoplastic polymer composition comprising:
• the polyolefin oligomer suitable for use in the present invention can be made from one or more suitable alpha-olefin monomers such as hexene-1, pentene-1, isopentene, ethylene, propylene, butene-1, isobutene, 4-methylpentene-l, butadiene, and mixtures thereof.
• an "oligomer" is defined as a macromolecular substance that has a number average molecular weight less than about 15,000 or a melt flow rate greater than about 300 grams/10 minutes at 230° C. and 2.16 kilograms, preferably over 1000 grams/10 minutes. The melt flow rate is measured in accordance with ASTM D-1238-86.
• the oligomer can be prepared by degrading a polyolefin.
• a specific example is the degrading of polypropylene in a melt blending reactor or extrusion with a free radical initiator.
• a suitable free radical degraded polyolefin can be a blend of 5% dicumyl peroxide and polypropylene prepared in accordance with the procedure disclosed in U.S. Pat. No. 4,451,589 to Moorman et al, which, when reacted in a melt blending or extruding operation, produces a polypropylene with a melt flow rate greater than 600 grams/10 minutes at 230° C. and 2160 grams.
• This blend could be used as a masterbatch in the present invention.
• a masterbatch is a concentrate which is subsequently used as one of the components in a formulation.
• the degraded polyolefin can also be prepared in situ by using a blend of polyolefin with a suitable degradant.
• Extruder modified polypropylene is also available in commercial grades from Exxon Chemical Company and Himont Chemical Company with melt flow rates varying from about 325 to greater than 2000.
• U.S. Pat. No. 4,282,076 to Boynton discloses this technology in the context of a process utilizing ionized radiation or oxidation.
• the polyolefin oligomer can also be a polyethylene or polypropylene wax, or preferably, amorphous or atactic polypropylene synthesized or produced as a byproduct in the manufacture of crystalline polypropylene.
• polyolefin co-oligomers produced by co-oligomerizing two or more monomers, such as propylene, isobutylene, butene-1, pentene-1.
• a suitable commercial formulation is sold by El Paso Products Company under the trademark Amorphous Polyalphaolefin (APAO), with grade variations identified as X-100, B3Al5, X-400, 311A, etc. All of the above mentioned materials can be used as the polyolefin oligomer, alone or in combination.
• APAO Amorphous Polyalphaolefin
• the olefinic or polyolefin elastomers suitable for use in the present invention have an elastic modulus of about 6000 psi or less at room temperature when measured in the uncrosslinked state in accordance with ASTM D638-72.
• the specific olefinic elastomers include ethylene-propylene copolymers, ethylene-propylene-diene terpolymers, ethylene-acrylic ester copolymers, polybutadiene, polyisoprene, natural rubber, isobutylene, and mixtures thereof. It is also contemplated that other equivalent elastomers which satisfy the elastic modulus requirement can also be used.
• the polyolefin elastomer can also include an oil extender, such as a naphthenic or paraffinic oil.
• the polyolefin thermoplastic polymer is a linear or branched polymer which can be repeatedly softened and made flowable when heated and returned to a hard state when cooled to room temperature. It generally has an elastic modulus greater than 6,000 psi using the method of ASTM D638-72. Thermoplastics can also be molded or extruded into articles of any predetermined shape when heated to the softened state.
• Suitable polyolefin thermoplastic polymers include an ethylene polymer, such as high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene vinyl acetate (EVA), ethylene methyl acrylate (EMA), and ethylene ethyl acrylate (EEA).
• ethylene polymer such as high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene vinyl acetate (EVA), ethylene methyl acrylate (EMA), and ethylene ethyl acrylate (EEA).
• Other suitable polyolefin thermoplastic polymers include polypropylene homopolymers and copolymers, poly(butene-1), poly(4-methylpentene-l), and other equivalent polyolefins.
• the polyolefin thermoplastic polymer component can be grafted or suitably modified with a monomer containing a dyeable functional group such as carboxylic acid and its derivatives, including anhydrides, acid chlorides, amides, imides and the like.
• a dyeable functional group such as carboxylic acid and its derivatives, including anhydrides, acid chlorides, amides, imides and the like.
• Other functional groups include amines, isocyanates and other reactive groups.
• a specific example of a dyeable component would be polypropylene grafted with acrylic acid or maleic anhydride or a copolymer of ethylene with methacrylic acid or acrylic acid.
• the relative proportion of the oligomer or degraded polyolefin to the olefinic elastomer cnn vary from about 90:10 to 20:80, preferably about 30:70 to 70:30, respectively.
• the proportion of the polyolefin thermoplastic polymer to the combined amount of the oligomer and olefinic elastomer can vary from about 0 to 30%, preferably 0.2 to 15%.
• part or all of the polyolefin thermoplastic polymer can be modified to provide dyeability to the composition.
• a suitable means for accomplishing the blending of the components of the inventive composition is to premix them and then extrude the blend composition through a heated extruder.
• Other mixing means such as a Brabender mixer, Banbury mixer, roll mills, single screw or multiple screw extruders, cokneaders, kneader-extruders, FCM mixers, gelmat mixers, and continuous and batch mixers can also be used.
• Processability is the ability to produce the blend in a process such as extrusion and to convert it into a film or fibers which can subsequently or simultaneously be converted to a woven or non-woven fabric for specific applications such as wipes or other suitable articles of clothing or articles of manufacture such as diapers, sanitary napkins, incontinent pads, bed pads, hospital gowns, and the like by conventional processes known to those skilled in the art.
• the processability of the blend composition can be evaluated for different applications by examining test specimens for surface finish smoothness and absence of imperfections. Although the criteria for processability as well as for pelletizability and drapability are qualitative, those skilled in the art are readily able to ascertain satisfactory products from those that are unsatisfactory by visual examination and touch.
• waste materials In most production situations, certain amounts of waste are generated.
• the ability to reprocess and reuse the waste materials can be a strong incentive in choosing a specific production composition.
• the inventive composition has been found to be reprocessable, and thus can be repelletized and reused.
• the ability to pelletize the inventive composition is important, because it would be difficult to convert the molten composition directly into fabrics by an extrusion process without pelletizing.
• the blend would be a gummy glob too large to feed into the processing equipment.
• Pelletizability was evaluated by attempting to dice the product from a rubber two-roll mill, or by underwater pelletizing, or stranding followed by cutting the strand into pellets.
• the composition was considered pelletizable if it could be pelletized by at least one of the above three methods. It has been found that where the melt flow rate (MFR) of the composition was below 800 grams/10 minutes, it was most convenient to pelletize. Thus, below a MFR of 800 grams/10 minutes, the blend was found to have "excellent pelletizability".
• MFR melt flow rate
• melt flow rate was obtained using condition "L” of ASTM method D1238-86 which is 230° C. and 2.16 kg. Most desirably, the ratio of the components was adjusted to obtain a melt flow rate of about 50 to 400 grams/10 minutes.
• Drapability is another important property or characteristic of the products formed from the inventive composition.
• An “excellent” rating was given if a film or a fabric prepared from the inventive composition had the drapability of an unstarched cotton handkerchief. Slightly stiffer fabrics and films were rated as “good”. Increasingly stiffer fabrics and films were judged to be “fair” or “poor”. The importance of drapability is evident in such applications as baby diapers or sanitary napkins since a drapable fabric is more comfortable on the skin than one that is not, especially when contacting the human skin for periods of time extending up to four hours or longer.
• the inventive composition can also include flame retardant materials, such as aluminum trihydrate, chlorinated and/or brominated or nitrogen-phosphorus-containing compounds. Flame retardant additives are generally included in amounts varying from about 5 to 40% by weight of total composition.
• Dusting agents such as talc, powdered high density polyethylene, chalk and other powders can be used to prevent massing of pellets in the final blend.
• Release agents such as stearates and silicones can be included to prevent sticking to blending equipment during processing.
• antiblocking agents and antistatic agents can also be included. However, the total amount of all additives should not exceed about 5% of the total weight of the inventive composition.
• composition can be converted to film or fabric material by any suitable method known to those skilled in the art, such as conventional cast or blown film extrusion, compression molding and sheeting, non-woven fabric processing, fabrication into wipes, extrusion melt spinning into fibers, followed by weaving into a fabric, or extrusion coating onto a synthetic or natural fabric such as cotton, paper, polyester, nylon, and the like.
• suitable method known to those skilled in the art, such as conventional cast or blown film extrusion, compression molding and sheeting, non-woven fabric processing, fabrication into wipes, extrusion melt spinning into fibers, followed by weaving into a fabric, or extrusion coating onto a synthetic or natural fabric such as cotton, paper, polyester, nylon, and the like.
• the fabric can be used for holding ultra-absorbents used in baby and adult diapers and sanitary napkins.
• a melt flow rate greater than 30, and preferably from about 80 to 200 grams/10 minutes at 230° C. and 2.16 kilograms (Cond. L). All melt flow rates in the examples and throughout the specification were measured at these conditions.
• Low density polyethylene (LDPE), ethylene vinyl acetate (EVA), and other polyethylene based raw materials were measured at 190° C. and 2.16 kilograms.
• a stabilizer masterbatch (containing 54.37% dilauryl thiodipropionate (DLTDP), 13.75% of Tinuvin 327 stabilizer from Ciba Geigy, 18.13% of Maglite D magnesium oxide from Merck & Co., and 13.75% of Irganox 1010 stabilizer from Ciba Geigy) and 16.65% of a peroxide modified polypropylene (35 MFR polypropylene modified with 5% Vulcup R peroxide from Hercles and 0.30% Lupersol 101 peroxide from Penwalt) was prepared in a Brabender melt mixer at 400° F. and 55 rpm for 7 minutes. The blend had the following properties: Instantaneous Shore hardness of 94A, excellent drapability, good pelletizability and a melt flow rate of 563 grams/10 minutes at condition L.
• DLTDP dilauryl thiodipropionate
• Tinuvin 327 stabilizer from Ciba Geigy 18.13% of Maglite
• EPDM ethylene-propylene-diene terpolymer elastomer
• MFR melt flow rate
• Example 1A This blend thus is identical to the one in Example 1A in preparation technique as well as ratios of components except where polymers of 11 MFR and 35 MFR were used in this example.
• Example 1A the corresponding oligomers were prepared from the same monomer, propylene.
• This blend gave the following properties: Instantaneous Shore hardness of > 99 A, poor drapability, excellent pelletizability and a melt flow rate of 3.2 grams/10 minutes at condition L. It is obvious that the hardness of this blend is too high to yield a "soft drapable material.” Also the low melt flow rate of 3.2 grams/10 minutes is too low to be useful as a drapable material because of its high viscosity.
• EPR ethylene propylene copolymer rubber
• This blend prepared in the same manner as in Examples 1A and 1B produced an Instantaneous Shore Hardness of 89A and an MFR of 57 grams/10 minutes, excellent pelletizability and medium drapability.
• Blends were prepared using the ingredients and weight % tabulated below in Table 1.
• EPR was same as used in Example 2, the polyolefin oligomer was Amorphous Poly (Alpha-Olefin) X-400 also called APAO B3Al5 available from El Paso Products Co.
• Blends similar to those in Examples 3-6 were prepared except that the olefinic elastomer was changed to the EPDM used in Example 1B, with the components, weight % and results tabulated in Table 2:
• This blend had a Shore Hardness of 69A, high melt flow rate of 868, excellent drapability and good pelletizability.
• Blends of the poly(alpha-olefin) oligomer used in Example 9 with the same peroxide-modified polypropylene used in Example 9 and the same ethylene-propylene diene polymer (EPDM) used in Example 1B with the same stabilizer masterbatch used in Example 1B were prepared. Blend ratios and properties are tabulated in Table 4 as follows:
• Blends were prepared with the same peroxide-modified polypropylene used in Examples 20 and 21, the poly (alpha-olefin) oligomer used in Example 9, the EPR used in Example 2 and the stabilizer masterbatch used in Example 1B.
• the blend ratios and properties are tabulated in Table 6 which follows, with the balance being the stabilizer:
• DSC differential scanning calorimeter
• Example 37 In the formulation of Example 37, 14.53% of the 17.03% EPDM was replaced by a 35 MFR polypropylene homopolymer.
• the Shore A hardness of this blend was 80A and 418 MFR with excellent pelletizability, good drapability and reprocessability.
• Example 38 The 35 MFR polypropylene of Example 38 was replaced by the polypropylene copolymer used in Example 35.
• the blend gave values of 390 MFR and 73A hardness on the Shore A scale with good pelletizability and excellent drapability.
• Blends were prepared using two polypropylenes grafted with acrylic acid, (PPgAA), one of which had a MFR of 12 and the other a MFR of 40, the same poly-olefin and EPDM as in Example 42, isobutene-butene copolymer used in Example 42 and the same stabilizer masterbatch used in Example 1B. Blend ratios and properties are tabulated in Table 7 as follows:
• Fibers, films and fabrics were prepared from the blends of Examples 44 to 49 and were dyed with two different cationic 5% dye solutions using standard dyeing procedures.
• One dye solution was made from Acrydine Orange and the other dye solution was made from Toluidene Blue. All six blends picked up the dye.
• Toluidene Blue-dipped samples gave violet-colored fibers, fabrics and films while the Acrydine Orange-dipped samples gave yellowish orange-colored articles, demonstrating that the blends had good dyeability as well.
• Control film samples prepared from th blends of Examples 35 and 36 (which did not contain the functionally modified polyolefin component) were run through the same dye solutions and these did not pick up any dye and remained colorless.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Materials For Medical Uses (AREA)
• Nonwoven Fabrics (AREA)

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• 1987
  • 1987-07-20 US US07/075,400 patent/US4833195A/en not_active Expired - Fee Related
• 1988
  • 1988-07-14 EP EP19880306467 patent/EP0300689A3/fr not_active Withdrawn
  • 1988-07-15 AU AU19106/88A patent/AU605888B2/en not_active Ceased
  • 1988-07-19 CA CA000572391A patent/CA1315434C/fr not_active Expired - Fee Related
  • 1988-07-19 NZ NZ225474A patent/NZ225474A/en unknown
  • 1988-07-20 JP JP63179281A patent/JPS6440546A/ja active Pending

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